FIGURE 3. MNA locality 318 on the south flank of House Mountain, Arizona. 3.1. View northward from across the canyon. Fossils were collected from the light-colored mudrocks in the center of the photograph beneath the horizontal limestone ledges extending across the photo. K. Davies points out the hollow in the outcrop behind him from which the blocks were quarried and plaster-jacketed for this study. 3.2. Close-up view northeastward of the same outcrop. K. Davies' right hand is on the level that contained the richest assortment of microvertebrate bones.